Motor for rock-drills and similar tools.



PATENTED APR. 9, 1907.

C. E. SHADALL. MOTOR FOR ROCK DRILLS AND SIMILAR TOOLS.

APPLIOATION FILED AUG. 8, 1904.

. UNITED STATES PATENT" OFFICE.

CHARLES E. SHADALL, OF MILWAUKEE, YVISCONSIN, ASSIGNOR OF ONE- HALF TO FREDERICK L. HORNEFFER, OF MILWAUKEE, WISCONSIN.

MOTOR FOR ROCK-DRILLS AND SIMILAR 'I 'OOL S.-

Specification of Letters Patent.

Patented April 9, 1 907.

Application filed August 8,1904. Serial No. 219,876.

. had to t e accompanying drawings, forming a partthereof. v

The main object of this invention is to operate rock-drills and similar tools directly by 'the explosion of gas or a mixture of air and gas or oil vapor .and to adapt an internalcombustion motor to perform this class of work.

It consists in certain novel features of construction. and in the peculiar arrangement and combinations of parts, as hereinafter particularly described, and pointed out in'the claims.

In the accompanying drawings like 'letters designate the same parts inthe several figures.

Figure 1 is a vertical medial section on the line 1 1, Figs. 2 and 3, of a motor embodying the invention. Fig. 2 is a similar section at right angles to that of Fig. 1 on'the line 2 2, Figs. 1 and 3. v Fig. 3 is a cross-section on the line 3 3, Fig. 2; v and Fig. 4 is a cross-section on the line 4 4, Fig. 1.

The motor herein shown and described is an internal-combustion engine of the twocycle type in which the charge is ignited at every working stroke of the engine.

Referring to the drawings, a is a differential cylinder having smaller and larger coaxial parts or bores, and bis a differential piston fitted to work in the two parts of said cylinder. 40: The cylinder is formed or provided on one side +wah a passage 0, connecting the smaller end- I of the cylinder with the adjacent end of the larger part thereof. This passage is provided with a check-valve d, which opens toward the smaller end of the cylinder. The cylinderis also formed or providedwith an airsupply passage or connection e, which communicates with the passage 0 below the valve (1, or it may be made to open into the larger art of the cylinder next to the smaller part 7 independently of said passage 0. It is provided with a spring-seated check-valve f, which opens inwardly.

- g is a gas or 011 supply connection which 'der.

From the upper smaller end of the cylinder an exhaustassage 9' leads into the exhaustvalve cham er k on one side of thecylinder and thencethrough ports in the valve-bushing into'a passage Z, opening to the atmosphere. cock m for throttling the exhaust, and thereby regulating the speed of the piston or the fre uency of its active or working strokes by chec 'n its movement more or less on the. return stro es.

The passage Z is provided with-a n is a reciprocating exhaust-valve fitted to work in the bushing in the chamber lc and normally closing the ports in said bushing.

Its stem is guided at its lower end in a bearing provided therefor on the lower end of the cylinder,,and it is held normall closed by a latch 0, consisting of an angu ar lever fulcrumed at its angle to a bracket or housin p, which is formed on or attached to the cy ina latch blook g, which is normally held by a s ring 1 in engagement with a corresponding b fock s onthe valve-stem. The other arm of said lever roj ects, normally into the path of a weighted cam t, which is loosely or pivotally mounted on a rocker-shaft a, supported horizontally and transversely to the cylinder by hearings in. the housing; 12. .Upon this shaft are fixed two arms-v, one on each side of'the cam t, and the free ends of these arms are held by torsion-springs w in engagement with the lower end of the piston b, the springs w bein attached at one end to collars on the ends 0% the shaft 11. and at the other end to the housin p. The weighted arm of the cam t is he (I normally by a sprin :0 against lower end of the stem pf the exhaust-valve to close said valve in the upwardorreturn move- One arm of this lever is provided with During ment of the rocker and piston. One of the arms 0 is rovided with a in 2, arranged to engage with the lower end of the plunger i and to move it upward against the tensionof a retracting-spring 2.

by a pawl 6, pivoted to the cylinder in said recess, as shown in Fig. 4, but is permitted to turn in the other direction. A stop 7 is. attached to the lower end of the cylinder to prevent the downward movement of the piston beyond a certain extreme limit.

In Fig. 1, 8 designates a plug provided in the usual or any suitable manner with sparking points or electrodes (not shown) for igoperations above explained will be repeated.

niting the charge at the beginning of each 5 working stroke of the piston, and 9 is a spring-contact arranged to be engaged by the i in z and to close and break the circuit of the l igniter in the usual or any suitable manner at or near the upper limit of the return strokes of the piston. On one side the cylinder is formed or provided with a nut 10, as shown in Fig. 2, by which it is connected with an adjusting-screw parallel with the axis of the cylinder for moving the drill or other tool, with the motor, toward and from its work and for feeding the tool forward, with the motor, as the work' progresses. This adjustingscrew and the frame or stand carrying it in the well-known manner common to rockdrills constitute no part of the present invention and are therefore not shown.

The motor herein shown and described operates as follows: A charge of gas or oil vapor mixed with air bein introduced into the upper end of the cylin er and compressed is exploded by the sparking or other igniting device, imparting a quick downward movement to the piston and causing the drill or other tool attached thereto to strike a sharp blow. the downward movement or active stroke of the piston air is drawn throu h the passage 6 into the cylinder above the arger part of the piston, the valve (1 being closed while the valve f is opened to admit air.

,''Upon the termination of the downward stroke of the piston the weighted arm of the cam 25 is carried by its momentum against the tension of the spring as beyond the limit of the movement of the piston and rocker and causes the cam t to engage with and trip the latch 0, thereby releasing the exhaust-valve, whicl'i is opened by gravity, or, if necessary or desirable, by a spring. The spent charge in the up er end of the cylinder now escapes throng the exhaust-passage 7' and the pas sage Z to the atmosphere, and the piston'is returned to its initial position by the action of the springs w through the rocker-arms v. The return stroke of the piston forces the air drawn into the larger part of the cylinder during the downward or working stroke of the piston through the passage 0 into the up per end of the cylinder above the smaller part of the piston. As the piston approaches the upper limit of its movement the pin a, moving the plunger i upward past the gas or oil supply connection g, forces a charge of gas or oil into the passage 0, through which it is entrained with air into the upper end of the cylinder. The exhaust-valve being closed by the engagement of the cross-bar y with the lower end of its stem in the upward movement of the rocker, the charge of gas or oil vapor mingled withthe air in the upper end of the cylinder is com ress'ed sufliciently to be ignited and explo ed by a spark or other igniting device, whereupon the cycle of In the downward or working stroke of the piston the ratchet-Wheel 5 is turned to the right by the inclined grooves 4 and the projections in the ratchet-wheel engaging therewith, and in its upward movement the piston itself is turned to the right by the action of said grooves and projections, the ratchetwheel being held from turning back to the left by the pawl 6. other tool is turned step by step between its- In this way the drill or successive blows, according to the usualop-- eration of rock-drills. By partially closing the passage l with the cock m and throttling the exhaust the .upward movement-of the piston is retarded, and the tool is thus caused to strike less frequent blows. By increasing the exhaust-opening the motor is caused to work more rapidly.

.Various changes'in minor details of construction and in the arrangement of parts 'may bemad e within the principle and inintended scope of the invention.

'' 1 cla1m "1. The combination of a cylinder, a iston ton in one direction, a spring tending to move said rocker in the opposite direction, a weighted cam loosely mounted on the rocker and adapted to be carried by its momentum beyond the limit of the active stroke of the iston sufliciently to trip said latch androease said valve, and a spring tendingt'o hold said cam against a stop on the rocker, substantially as described.

2. The combination of a cylinder, a piston fitted therein, an exhaust-valve adapted to be closed by the return stroke of the piston, a latch for holding said valve closed, a rocker arranged to be moved'in-one direction by. the active stroke of the piston, a spring tending to move said rocker in the reverse direction and to return the piston to its initial osition, a Weighted cam pivotally mounte on the rocker, and a spring normally holding said cape against a stop on the rocker, the cam being adapted to be carried by its momentum against the tension of the spring acting thereon beyond the limit of the active stroke of the iston and in its further movement to trip said latch and permit the valve to open, substantially as described.

3. The combination of a difierential cylinder having passages leading from an air-inlet opening into corresponding ends of the larger and smaller parts of the cylinder and connecting the same, a differential piston -fitted in said cylinder, inwardly-opening check-valves in said passages, a spring-actuated rocker arranged to return the piston to its initial position after each active stroke vided with an inwardly-opening check-valve,

and means operated by said rocker for forcing gas or oil into the smaller end of the cylinder during each return stroke of the piston, substantially as described.

4. The combination of a differential cylin- 'der having an air-supply passage opening into the larger part of the cylinder next to the smaller part and provided with an inwardly-opening check-valve and a passage connecting the smaller end of the cylinder With. the adjacent end of the larger part and provided with a check-valve which opens toward the smaller end of the cylinder, a differential piston litted in said cylinder, a springactua-ted rocker for returning said piston to its initial position, a gas or oil supply connection, means operated by said rocker for forcing gas or oil through said connection into the smaller end of the cylinder during each return stroke of the piston, an exhaust-passage opening out of the smaller end of the cylinder, a valve normally closing said exhaust assage, and means operated by said rocker or releasing and closing said valve at the proper times, substantially as described.

5. The combination of a differential cylinder having a passage connecting the smaller end of the cylinder with the adjacent end of the larger part thereof and provided with a actuated by said piston for injecting gas or oil vapor into the passage connecting the larger part with the smaller end of the cylinder, an exhaust port or passage opening out of the smaller end of the cylinder, a valve normally closing said port or passage, means operated by said rocker for releasing and closing said valve at the pr pcr times, and a cock for throttling the exhaust and regulating the move- I ment of the piston, subst antiallyas described. thereof, a gas or 011 supply connection pro- 6. The combination of a differential cylinder having a valve-controlled passage connecting its smaller end with the adjacent end of the larger part thereof and having a valvecontrolled air-supply connection opening into the larger part of the cylinder, a differential piston fitted in said cylinder, an exhaust-port opening out of the smaller end of the cylinder, a valve normally closing said port, a latch for holding said valve closed, a rocker arranged to be moved in one direction by the active stroke of the piston, a weighted cam pivotally mounted on said rocker and adapted to be carried by its momentum beyond the limit of the active stroke of the piston and to trip said latch, a spring normally holding said cam against a stop on the rocker, a

, spring adapled to return the rocker and piston to their initial positions and means actuated by the return movement of said rocker for injecting gas or oil vapor into the smaller end of the cylinder, sulistantially as described.

In Witness whereof I hereto affix my signature in presence of two witnesses,

CHARLES E. SILULXLL. Witnesses:

CHAS. L. Goss, A. F. WEST. 

